The present invention relates to an electronic watch, and is concerned in particular with the means for controlling the watch.
Whether they are analog display watches or digital display watches, watches are controlled in most cases by means of movable members which are accessible to the user of the watch. Such members may be for example push-buttons or sliding and rotary stems. Such means for controlling a watch give rise to two series of problems.
The first problem concerns the control member itself. On the one hand, the control members project outwardly from the watch casing, and they are of dubious easthetic nature. Then, and in particular as the control members are movable, they give raise to technological problems which are difficult to overcome, taking into account the requirements in regard to sealing them, reliability and cost, particularly when they are to be used in relatively thin watches.
In an attempt to overcome these first problems, arrangements have been designed, which act as an electronic control circuit-breaker switch which is based on the principle of detecting either a change in capacitance or a change in resistance when the user places his finger at a given point on the glass or the casing of the watch. The disadvantage of a capacitive-action arrangement is that it consumes a great deal of electrical power. In fact, the capacitive divider including the capacitor which is variable depending on the position of the finger must have an alternating current passing continuously through it. A resistive-action system suffers not only from the disadvantage of a high level of power consumption but of being particularly sensitive to dirt which clings to the surface of the watch casing. It is therefore difficult to ensure that this arrangement operates properly.
The second series of problems is linked to the increase in the number of functions performed by a watch, in particular when it is a digital display watch. The main function of any watch of course is to show the time. A varying number of auxiliary functions is added to that main function. In the simplest case, the only auxiliary function is setting the time shown by the watch. In fact this correction function covers two situations, either when the function involves altering the watch to set it to the correct time, in which case the correction involved is a few seconds or a few fractions of a minute per month, or changing the time zone shown by the watch, as required. A widely varying number of other auxiliary functions may be added to the above-discussed auxiliary function which is strictly necessary. Mention may be made of alarm or awakening functions which trigger for example a bell or buzzer when the watch reaches a pre-selected alarm time; a chronograph function with many variations; or yet again, a function involving starting a count-down or timer function. In order to carry out some of those functions, the watch simply has to be given an instruction in order to set the watch into a desired mode of operation. This is the case for example with the chronometer function. In other cases, not only must the watch be put into the desired mode of operation but in addition the watch must be supplied with digital data in order for the desired function to be introduced in its entirety. This is the case with changing the time zone, and it is also the situation involving introducing an alarm time, etc.
In order to control these different functions, that is to say, in order to introduce the different corresponding instructions into the watch by means of push-buttons or similar mechanisms, it is necessary either to multiply the number of push-buttons or to arrange for each control member to occupy a number of active positions which make it possible to make a distinction between the input of several different instructions, or yet again a combination of those two arrangements.
Where the watch includes a fair number of functions, such handling operations are tiresome for the user and give rise to the danger of causing many errors, more particularly when dealing with functions which are rarely used. Even when dealing with just the time setting function, it is necessary to make a distinction between an operation of correcting the minutes and an operation of correcting the hours. This distinction is often made on the basis of the period of time for which a push-button is actuated. It will be seen at once that a substantial number of errors or improper actuating operations may occur.
Another solution is proposed in Swiss Pat. No. 621 460. This solution comprises providing the watch with a microphone which receives a sound signal for controlling the functions of the watch. However, the sound signal must be coded in a highly precise manner in order for the electrical signal supplied by the microphone to form a coded signal which can be used directly by the watch. It will be seen therefore that the watch can be controlled only if this coded signal sound source is available. This greatly limits the freedom of controlling the watch and the real application of such a control system is actually limited to setting the time shown by the watch.
The said Swiss Patent also describes the possibility of stopping the alarm of the watch by a verbal instruction. In actual fact, that verbal instruction is unique since there is only one function to be controlled, namely stopping the alarm. In actual fact therefore, that verbal instruction is entirely comparable to a noise emitted by the person using the watch. Therefore, that solution is only a very partial solution and in no way overcomes the problem involved.